Sika Sarnafil World Class Roofing and Waterproofing ROOFING TECHNICAL BULLETIN #07-12 To: Authorized Roofing Applicators Sika Sarnafil Sales Staff & Sales Representatives Sika Sarnafil Regional Technical Staff Sika Sarnafil Customer Service Staff Sika Sarnafil Services Staff Roofing Consultants From: Technical Service Department Date: October 10, 2012 Subject: Sarnacol 2121 Application Guide All adhesive quantities listed in Sika Sarnafil data sheets, specifications, handbooks, etc. represent the minimum amount of adhesive to be used. In some instances, the amount of labor required to achieve a given coverage rate needs to be considered against potential material savings. For most surfaces (excluding concrete, cellular concrete, and Densdeck-unprimed) 133 ft²/gal (3.27m²/L) is the necessary amount of Sarnacol 2121 required to properly adhere G-410 membrane. The application technique used will determine the actual coverage rate achieved. To achieve the best approved coverage rate of 133 ft²/gal (3.27m²/L) consistently, Sarnacol 2121 should be sprayed using an airless sprayer. Our Sarnacol 2121 Application Guide which explains the three application techniques that can be used for Sarnacol 2121 (squeegee, roller, and spray) and the applicable coverage rates for each is attached. For additional questions please contact Sika Sarnafil s Technical Department. Sika Sarnafil, A Division of Sika Corporation, 100 Dan Road, Canton, MA 02021 Tel. 8004512504, Fax: 7818285365, www.sikacorp.com
Sarnacol 2121 Application Guide Sarnacol 2121 is a water-based dispersion adhesive used within a Sika Sarnafil Adhered system. It is formulated for adhering PVC membranes to clean, dry, water absorbent, horizontal roof surfaces with slopes up to 10 or 2 /12 (5cm/30cm) 1 when using the methods of installation noted below. Precautionary measures must be taken to avoid exposing Sarnacol 2121 to low temperatures. Sarnacol 2121 may only be used when temperatures are 40 F (5 C) and rising. Sarnacol 2121 should not be used when temperatures are expected to fall below 40 F (5 C) during the initial curing period of 72 hours. In cool or humid weather Sarnacol 2121 will take longer to cure. Sarnacol 2121 is designed as a one sided wet lay in so there is no adhesive flash off time which results in faster membrane application. Notched Squeegee Application Sarnacol 2121 can be applied with a notched-squeegee for both bareback and felt backed membrane applications. The adhesive is applied to the substrate only. When aligning the membrane, the sheets can either be pulled back lengthwise or they can be aligned in a butterfly or barn door method where the membrane is pulled back across the width of the sheet. The adhesive is poured onto the substrate in ribbons and then spread evenly with a notched squeegee. The membrane is then rolled into the adhesive while it is still wet and immediately broomed into place with a medium bristle push broom to work out any air bubbles. Push the broom down the center of the sheet followed by brooming out from the center on both sides. Immediately after brooming, roll the membrane in both directions with a minimum 100 lb (45 kg), steel, membrane roller. Clean any adhesive residue on the seams while still wet and before welding. If the adhesive dries in the seam it will require a solvent to clean it. Roller Application Sarnacol 2121 can be applied using a 3/8-1/2 (9.5mm 12.7mm) medium nap roller for both bareback and felt backed membrane applications. The adhesive is applied to the substrate only. The adhesive is poured onto the substrate in ribbons followed by rolling and spreading evenly. Using rollers up to 18 (45.7cm) wide will improve application time. Coverage rate for most substrates is improved up to 33% when using the roller application method vs. the squeegee application (see coverage rates below). When applying 2121 with a roller at the reduced coverage rates, it is important to remember that Sarnacol 2121 is still a product designed for wet lay in. When applied with a roller at the improved coverage rate, care must be taken to insure that the adhesive has not dried before the membrane is laid in place. This is especially important during applications at high temperatures. When using the roller application, the membrane should be aligned by pulling the sheets back lengthwise rather than using the barn door method. The barn door method will result in long open times likely resulting in dry laid membrane. To insure a wet lay in, it is recommended that only 3-4 ft (0.9-1.2 m) at a time is coated out ahead of the membrane. The membrane is then rolled into the adhesive while it is still wet and immediately broomed into place with a medium bristle push broom to work out any air bubbles. Push the broom down the center of the sheet followed by brooming out from the center on both sides. Immediately after brooming, roll the membrane in both directions with a minimum 100 lb (45 kg), steel, membrane roller. Clean any adhesive residue on the seams while still wet and before welding. If the adhesive dries in the seam it will require a solvent to clean it. Applying Sarnacol 2121 using a roller application rather than a notched squeegee will provide some significant benefits while achieving the same high strength bonding performance. The benefits of using the roller applied method are: Reduced adhesive material cost. Approximate savings up to 33% on adhesive material consumption, compared to the squeegee method of application, with no additional labor expense. Faster adhesive drying time. Less adhesive means faster drying time while still achieving FM approvals for uplift and fire. For specific FM and UL ratings please contact Sika Sarnafil. Better Aesthetics. When a notched squeegee is used to apply Sarnacol 2121, the squeegee pattern may telegraph through to the roof surface over time. With a roller application there are no squeegee lines. 1 For information on using Sarnacol 2121 on higher slopes see Technical Bulletin 3-09 and for use on flashings see Technical Bulletin 4-09.
Spray Application of Sarnacol 2121 Sarnacol 2121 can also be applied using an airless spray applicator. Spraying 2121 can improve coverage rate over the squeegee application up to 50%. Equipment Typically airless sprayers are characterized by their spray rate, listed as gallons per minute (GPM) and their maximum pressure, listed as pounds per square inch (PSI). To spray Sarnacol 2121 the airless sprayer must be able to generate pressure up to 3000 PSI(211 kg/cm²) and should be able to deliver a minimum of 1.5 GPM (5.6 L/min). Larger units will allow for longer hose runs and increased production. A typical airless pump sprayer. A gas powered, hydraulic sprayer shown here is capable of dispensing up to 4 gallons per minute. The hose for pumping Sarnacol 2121 should be a minimum of ½ (12.7mm) diameter coming out of the machine. Reducing down to a 3/8 (9.5mm) whip 10 (3.1m) long leading up to the gun will make it easier to control. Always check with the equipment manufacturer for their recommendations. Sarnacol 2121 has a high viscosity and may clog the filters of the airless sprayer. It is recommended that all filters in the spray rig and spray gun be removed. When the filters are removed it is important to keep debris out of the adhesive container to prevent clogging at the spray tip. Always check with the manufacturer before making any modifications to the equipment. Always read the spray equipment manufacturer s product literature, labels and other information completely before use. Spray gun- The gun should be recommended by the manufacturer for use with that specific airless sprayer. An extension wand can be added to most guns to make spraying more comfortable and to keep the spray away from the operator. A swivel tip allows for proper angling of the spray pattern.
The spray tip will ultimately determine the flow rate of the adhesive. A tip that is too small will result in clogging. A tip size of.027-.035 inches (.68 -.88 mm) should be the minimum orifice opening, however, the tip size can be increased to.045 inches (1.1mm) for greater throughput. The fan pattern size is to be determined by the user. A bigger fan pattern will cover more area faster but will be more difficult to control and will be more prone to overspray. Generally a fan pattern of 10-12 inches (25.4 30.5 cm) wide held one foot (30.5cm) off of the substrate works well. Consult the airless sprayer manufacturer for compatible tips and sizes. Many tips are reversible for self cleaning. If clogged, engage trigger lock, reverse tip, disengage trigger lock and pull trigger to pump coating through orifice at high pressure to blow out dried/clogged material. Coverage rate Once the tip size and fan pattern are determined the coverage rate will be dictated by the walking speed of the operator. Counting the pails used is generally the best method to confirm the coverage rate. However, overspray and bounce back may result in lower coverage than indicated by counting pails. A wet mil thickness gage should be used to confirm adhesive thickness. To achieve 133 100 ft²/gal (3.27 2.47 m²/l) coverage the wet mil thickness of the adhesive should be approximately 12-16 mils wet. Application Prepare the membrane to be adhered by aligning as many rolls as are to be installed in a day. Unroll the membrane completely and position to achieve the required overlap. Either roll back or pull back the membrane lengthwise, ½ way (50 [15.2m] of a 100 [30.5m] roll). If the membrane can be rolled back evenly as opposed to pulled back, this is the preferred method. By rolling back the membrane rather than pulling the sheet onto the other half, the adhesive application can be done with fewer workers and can be rolled immediately after adhesive application. Do not use the barn door method of opening the sheets when spraying Sarnacol 2121 as this will result in long open times and likely dry laid membrane.
By rolling the membrane back evenly there is very little chance of dry laying the sheet as brooming and rolling can follow immediately behind the sheet while the adhesive is wet. This method is also less likely to induce air bubbles compared with pulling the sheets back onto the other half and requires fewer workers to install. This is typically a 5 man operation. 1- Spray operator 1- Hose man/monitor keeping the hose out of the way and alerting the spray operator of roof obstacles and roof perimeter. 1- Man rolling membrane into place and following right behind with a weighted roller. 1- Man assisting with rolling and making sure any overspray is quickly removed from the seam area of the preceding sheet. 1- Man attending the spray rig and assuring adhesive is mixed and the spray bucket is full. When the sheets are pulled back rather than rolled back, it takes 2 workers to pull the sheet into the wet adhesive and it delays brooming and rolling until the top sheet is out of the way. This method requires a minimum of 6 workers. 1- Spray operator 1- Hose man/monitor keeping the hose out of the way and alerting the spray operator of roof obstacles and roof perimeter. 2- Men pulling the sheet into place. 1- Man brooming/rolling with a weighted roller. 1- Man attending spray rig and assuring adhesive is mixed and the spray bucket is full.
Prior to spraying, mix Sarnacol 2121 with a mechanical mixer until achieving a smooth consistency with no clumps. Start the airless sprayer with the pressure settings low and make adjustments upwards until the spray pattern is even without tails or fingers. Run the spray pump at the lowest pressure setting possible while still achieving a good spray pattern. The lower the pressure the less overspray and bounce back will occur preserving material and minimizing cleanup. Adhesive should not be applied more than 3-4 ft (0.9-1.2 m) in front of the membrane. While moving the gun from side to side it is recommended to trigger the gun on and off when reaching the edge. This will prevent buildup at the edges and prevent contaminating the seams when rolled with the weighted roller. It is not necessary to overlap the preceding pass assuming proper coverage is obtained with a single pass. The membrane should be rolled/pulled into place as soon as practical. The membrane must be broomed immediately to remove air bubbles. Run the broom down the middle of the sheet and then push from the middle out to each edge. Brooming works much better in removing air pockets but rolling with the 100 lb (45 kg) weighted roller immediately after or concurrent with brooming is also critical to insure proper embedment into the adhesive. Clean all overspray out of the laps while the adhesive is still wet and before welding. If the adhesive dries in the seam it will require a solvent to clean it. *Most airless sprayers have the capability of attaching one or more pressure rollers. With a pressure roller, the adhesive is pumped through the spray gun to a slotted, medium nap roller and controlled by the gun trigger. This can be a good option on windy days. Applying Sarnacol 2121 using the spray application rather than a notched squeegee will provide some significant benefits while achieving the same high strength bonding performance. The benefits of using the spray applied method are: Reduced labor costs due to speed of application with fewer personnel. Reduced material costs of up to 50% due to better coverage rate compared to the squeegee method. Faster dry time. Better aesthetics compared to the squeegee method. For additional questions please contact the Sika Sarnafil Technical Department.
Sarnacol 2121 Coverage Rates Substrate Squeegee Applied Roller Applied Spray Applied Bareback Membrane Rates Isocyanurate Facer 67 ft² /gal 100 ft²/gal 133 ft²/gal Isocyanurate Glass Facer 80 ft²/gal 100 ft²/gal 133 ft²/gal (1.96 m²/l) (2.47 m²/l) (3.27m²/L) Smooth Plywood 67 ft² /gal 100 ft²/gal 133 ft²/gal Dens-Deck Prime 80 ft²/gal 100 ft²/gal 133 ft²/gal (1.96 m²/l) (2.47 m²/l) (3.27m²/L) Securerock Gypsum Fiber 80 ft²/gal 100 ft²/gal 133 ft²/gal (1.96 m²/l) (2.47 m²/l) (3.27m²/L) Substrate Squeegee Applied Roller Applied Spray Applied Feltback Membrane Rate Isocyanurate Facer 57 ft² /gal 100 ft²/gal 133 ft²/gal (1.41 m²/l) (2.47 m²/l) (3.27m²/L) Isocyanurate Glass Facer 67 ft²/gal 100 ft²/gal 133 ft²/gal Smooth Plywood 57 ft² /gal 100 ft²/gal 133 ft²/gal (1.41 m²/l) (2.47 m²/l) (3.27m²/L) Concrete Deck 50 ft²/gal 100 ft²/gal 100 ft²/gal (1.23 m²/l) (2.47 m²/l) (2.47 m²/l) Cellular Concrete 50 ft²/gal 100 ft²/gal 100 ft²/gal (1.23 m²/l) (2.47 m²/l) (2.47 m²/l) Dens-Deck 57 ft² /gal 100 ft²/gal 100 ft²/gal (1.41 m²/l) (2.47 m²/l) (2.47 m²/l) Dens-Deck Prime 67 ft² /gal 100 ft²/gal 133 ft²/gal Securerock Gypsum Fiber 67 ft² /gal 100 ft²/gal 133 ft²/gal